/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package com.hw.lineage.flink;

import org.apache.calcite.sql.SqlBasicCall;
import org.apache.calcite.sql.SqlCall;
import org.apache.calcite.sql.SqlFunction;
import org.apache.calcite.sql.SqlIdentifier;
import org.apache.calcite.sql.util.SqlBasicVisitor;
import org.apache.flink.table.catalog.UnresolvedIdentifier;

import java.util.ArrayList;
import java.util.List;

/**
 * @description: FunctionVisitor
 * @author: HamaWhite
 */
public class FunctionVisitor extends SqlBasicVisitor<Void> {

    private final List<UnresolvedIdentifier> functionList = new ArrayList<>();

    @Override
    public Void visit(SqlCall call) {
        if (call instanceof SqlBasicCall && call.getOperator() instanceof SqlFunction) {
            SqlFunction function = (SqlFunction) call.getOperator();
            SqlIdentifier opName = function.getNameAsId();

            functionList.add(UnresolvedIdentifier.of(opName.names));
        }
        return super.visit(call);
    }

    public List<UnresolvedIdentifier> getFunctionList() {
        return functionList;
    }
}
